Method for controlling ignition of an internal combustion engine

ABSTRACT

A method for controlling the ignition of an internal combustion engine ( 10 ) for a motor vehicle. More specifically, the method controls the timing of ignition for each of cylinder of the internal combustion engine ( 10 ). Control of the timing is based on two parameters, i.e., the speed at which the internal combustion engine ( 10 ) is operating and the gear in which the transmission ( 22 ) is operating. The speed is measured in terms of revolutions per minute. The gear helps to gauge what type of load may be present on the internal combustion engine ( 10 ). By identifying each of these parameters, it may easily be determined at what value the timing may be. If the specific speed of the vehicle is not located within the look-up table, where the data is stored, the method will interpolate the timing value based on values close to the value of the speed of the internal combustion engine ( 10 ) based on the neighboring values thereof.

BACKGROUND ART

[0001] 1. Field of the Invention

[0002] The invention relates to a method for controlling the ignition ofan internal combustion engine. More specifically, the invention relatesto a method for modifying the timing associated with the ignition ofindividual cylinders of an internal combustion engine of a motorvehicle.

[0003] 2. Description of the Related Art

[0004] Ignition control of an internal combustion engine is important toenthusiasts that want to optimize the operation of their motor vehicles.Each ignition in each cylinder must be optimized in order to maximizethe performance of an internal combustion engine.

[0005] Oftentimes, control of ignition is elaborate. Vibrations,pressures, temperatures and other parameters of an internal combustionengine are measured constantly. The timing of the ignition is advancedor retarded from top dead center depending on the measurements. Thetiming can change from cycle to cycle or from operating condition tooperating condition and the timing of the ignition is changedcontinually.

[0006] These types of systems are complex in design and operation.Further, these types of systems require hardware that, in manyinstances, must be installed during the manufacture of the internalcombustion engine. Therefore, these systems are inappropriate for thosethat are seeking to improve the performance of the internal combustionengine after it has been manufactured and operated.

SUMMARY OF THE INVENTION

[0007] A method is disclosed for controlling the timing of the ignitionin each of a plurality of cylinders of an internal combustion enginethat is used to power a transmission having a plurality of gears. Thetransmission is powered by the internal combustion engine through acrankshaft. The method includes the step of identifying the geartransmitting power generation from the internal combustion engine. Themethod then measures the revolutions per minute for the internalcombustion engine. The method establishes a measured revolution perminute value. The method then generates a timing parameter for ignitionfor each of the cylinders of the internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Other advantages of the invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings, wherein:

[0009]FIG. 1 is a perspective view of an internal combustion engine,partially cut away, incorporating one embodiment of the invention; and

[0010]FIG. 2 is a logic diagram of one embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011] Referring to FIG. 1, a perspective view of an engine for a motorvehicle is generally indicated at 10. The engine 10 is an internalcombustion engine. The internal combustion engine 10 may include adistributor 12 or, in the alternative, it may include an electronicset-up more appropriate for operation with an electronic fuel injectorsystem (neither shown). The internal combustion engine 10 is controlledby an engine control unit 14. A bus, graphically represented by line 16,is used to communicate commands and data transfer between the enginecontrol unit 14, the various electronic components and sensors employedby the internal combustion engine 10. The engine control unit (“ECU”) 14provides all electrical and electronic communication between the varioussubsystems of the internal combustion engine 10 and other systems of themotor vehicle (none shown). The ECU 14 will be described in greaterdetail subsequently. The internal combustion engine 10 includes aplurality of cylinders represented in FIG. 1 by each of the electricalwires 18 that extend out of the distributor 12. Each of the cylindersincludes a piston and at least one intake and exhaust valve (noneshown). The valves are moved by a camshaft and the pistons move acrankshaft 18 as is well known in the art.

[0012] The crankshaft 18 extends into a torque converter 20, which ismechanically connected to a transmission 22. The transmission 22,partially cut away in FIG. 1, includes a plurality of gears 23, whichare selected either automatically or manually to determine theconversion of the torque generated by the torque converter 20 to therotational speed of the wheels of the motor vehicle (neither shown).

[0013] Referring to FIG. 2, a logic diagram of the method according tothe invention is generally indicated at 24. The method begins at 26. TheECU 14 measures a parameter or output of the internal combustion engine10 at 27. In the preferred embodiment, the output measured is the amountof revolutions made per minute (RPM) by the crankshaft 18 of theinternal combustion engine 10. The ECU 14 identifies the gear 23 inwhich the transmission 22 is currently operating at 28. Using theinformation of which gear the transmission 22 is in, the ECU 14 uses alook-up table at 30 to determine the timing, i.e., advance or retard, ofthe ignition for a particular cylinder. The look-up table includes a rowof data for every gear found in the transmission 22. In one embodiment,the table also includes sixteen columns. Each of the sixteen columnsidentifies the value for the revolutions per minute (RPM) of thecrankshaft. It may be appreciated by those skilled in the art that theremay be any number of gears 23 in the transmission 22 and there may beany number of columns delineating graduations in revolutions per minute.

[0014] Once the ECU 14 accesses the look-up table, it determines whetherthe specific RPM is represented in the look-up table. This step isperformed at 32. If the specific value for the RPM is represented in thelook-up table, the timing for a particular ignition for a particularcylinder of the internal combustion engine 10 is generated at 34.

[0015] If the specific value for the RPM is not represented in thelook-up table, the ECU 14 collects values in cells adjacent the valueclosest to the measured RPM at 36. Once these values are collected, theECU 14 linearly interpolates these values at 38 to identify a timingparameter for the ignition at 34. The method then returns at 40 to beginthe process again at 26. This process is done for each cylinderindependently of the others allowing spark advances or retardationsbased on the individual cylinder being fired.

[0016] The timing of the ignition for a particular cylinder isdetermined to optimize the combustion characteristics of the fuel foundin the particular cylinder of the internal combustion engine 10. If thetiming advances too far, the fuel in the cylinder of the internalcombustion engine 10 will detonate. Detonation is often referred to as“knock.” This phenomenon is undesired because it reduces the performanceof the internal combustion engine 10 and jeopardizes the integrity ofthe internal combustion engine 10. By not advancing the timing of theignition, performance is compromised resulting in a reduced fueleconomy. By utilizing the look-up table, the timing of the ignition offuel in a cylinder can be more highly tuned wherein the tuning is afunction of the gear in which the transmission 22 is operating.Identifying the gear 23 currently being used by the transmission 22 addssophistication to the ability to time the ignition of fuel in thecylinders of the internal combustion engine 10.

[0017] The invention has been described in an illustrative manner. It isto be understood that the terminology which has been used is intended tobe in the nature of words of description rather than of limitation.

[0018] Many modifications and variations of the invention are possiblein light of the above teachings. Therefore, within the scope of theappended claims, the invention may be practiced other than asspecifically described.

We claim:
 1. A method for controlling the timing of ignition in each ofa plurality of cylinders of an internal combustion engine used to powera transmission having a plurality of gears through a crankshaft, themethod comprising the steps of: identifying the gear transmitting powergeneration from the internal combustion engine; measuring a speed ofoperation for the internal combustion engine; and generating timingparameter for ignition for each of the cylinders of the internalcombustion engine.
 2. A method as set forth in claim 1 wherein the stepof generating timing parameters includes the step of identifying thetiming parameters using a look-up table.
 3. A method as set forth inclaim 2 wherein the step of measuring a speed of operation includesmeasuring the revolutions per minute of the crankshaft of the internalcombustion engine to establish a measured revolution per minute value.4. A method as set forth in claim 3 including the step of determiningwhether the measured revolution per minute value is represented in thelook-up table.
 5. A method as set forth in claim 4 including the step ofinterpolating the timing parameters from member values of the look-uptable close to the measured revolution per minute value.
 6. A method asset forth in claim 5 including the step of collecting values forrevolutions per minute from cells in the look-up table that are close tothe measured revolution per minute value.
 7. A method for controllingthe timing of ignition in each of a plurality of cylinders of aninternal combustion engine used to power a transmission having aplurality of gears through a crankshaft, the method comprising the stepsof: identifying the gear transmitting power generation from the internalcombustion engine; measuring revolutions per minute for the internalcombustion engine to establish a measured revolution per minute value;and generating timing parameter for ignition for each of the cylindersof the internal combustion engine.
 8. A method as set forth in claim 7wherein the step of generating timing parameters includes the step ofidentifying the timing parameters using a look-up table.
 9. A method asset forth in claim 8 including the step of determining whether themeasured revolution per minute value is represented in the look-uptable.
 10. A method as set forth in claim 9 including the step ofinterpolating the timing parameters from member values of the look-uptable close to the measured revolution per minute value.
 11. A method asset forth in claim 10 including the step of collecting values forrevolutions per minute from cells in the look-up table that are close tothe measured revolution per minute value.